When in doubt, use coconut oil! Anti-inflammatory, antimicrobial, and also incredibly tasty, coconut oil is almost fail-safe when it comes to getting rid of canker sores.
You will need…
Using clean hands or a cotton swab, dab a liberal amount of coconut oil onto the sore. Try to get a somewhat thick layer or clump on there-coconut oil melts rapidly and a thin layer just seems to slide right off. If you feel like you really can’t get it to stick, melt 1 tablespoon down with ½ teaspoon or so of beeswax to thicken it.